Herbicidal 2-ureido-benzamides

ABSTRACT

2-UREIDO-BENZAMIDES OF THE FORMULA   1-(NH2-CO-),2-(R3-N(-R4)-CO-N(-R2)-),(R1)N-BENZENE   WHEREIN R1 REPRESENTS HALOGEN, LOWER ALKYL OR LOWER ALKOXY OF AT MOST 5 CARBON ATOMS, R2 REPRESENTS HYDROGEN OR LOWER ALKYL OR AT MOST 5 CARBON ATOMS, R3 REPRESENTS HYDROGEN, LOWER ALKYL OR LOWER ALKOXY OF AT MOST 5 CARBON ATOMS, R4 REPRESENTS AN ALKYL, ALKENYL OR ALKYNYL RADICAL WITH AT MOST 8 CARBON ATOMS, LOWER HALOGEN-ALKYL, ALKOXYALKYL OR ALKYLMERCAPTOALKYL OF AT MOST 5 CARBON ATOMS OR CYCLOALKYL HAVING 3 TO 10 CARBON ATOMS AS RING MEMBERS, AND N REPRESENTS A WHOLE NUMBER FROM 0 TO 3, ARE DISCLOSED AS HERBICIDALLY ACTIVE COMPOUNDS OF ENHANCED TOXICITY TO UNDESIRABLE PLANT GROWTH AND IMPROVED SELECTIVITY. A METHOD FOR CONTROLLING UNDESIRABLE PLANT GROWTH WITH SUCH COMPOUNDS AND COMPOSITIONS CONTAINING THEM AS ACTIVE INGREDIENTS ARE ALSO DISCLOSED.

nited States Patent O 3,806,33 HERBICIDAL Z-UREIDO-BENZAMIDES KarlHoegerle, Basel, Switzerland, Jean-Claude Muller, St. Louis, France, andChristian Vogel and Jurg Rumpf, Binningen, near Basel, Switzerland,assignors to Ciba-Geigy Corporation, Ardsley, N .Y.

No Drawing. Original application Mar. 24, 1969, Ser. No. 809,978, nowPatent No. 3,646,136. Divided and this application Nov. 19, 1971, Ser.No. 200,598

Int, Cl. A01n 9/22 Us. at 71-120 8 Claims ABSTRACT OF THE DISCLOSURE2-nreido-benzamides of the formula C ONH: (R1).

I;ICN R: g R;

wherein are disclosed as herbicidally active compounds of enhancedtoxicity to undesirableplant growth and improved selectivity. A methodfor controlling undesirable plant growth with such compounds andcompositions containing them as active ingredients are also disclosed.

This is a division of application Ser. No. 809,978, filed on Mar. 24,1971, now US. Pat. 3,646,136.

DESCRIPTION OF THE INVENTION The present invention concerns herbicidal2-ureidobenzamides, processes for the production thereof, a method forcontrolling undesirable plant growth with the aid of the2-ureido-benzamides as well as compositions containing the herbicidallyactive substances.

More particularly, the invention provides Z-ureidobenzamides of theGeneral Formula I wherein R represents halogen, lower alkyl or loweralkoxy of at most carbon'atoms,

R represents hydrogen or lower alkyl of at most 5 carbon atoms,

R represents hydrogen, lower alkyl or lower alkoxy of at most 5 carbonatoms,

R represents an alkyl, alkenyl or alkynyl radical with at most 8, carbonatoms, lower halogen-alkyl, alkoxyalkyl or alkylmercaptoalkyl of at most5 carbon atoms or cycloalkyl having 3 to carbon atoms as ring member,and

n represents a whole number from 0 to 3,

which are useful in the control of undesirable plant growth, especiallyin the control of weeds and wild grasses.

As lower halogen-alkyl radical R represents an alkyl radical having 1 to5 carbon atoms, as previously stated, which may. be monoorpoly-substituted by fluorine, chlorine and/or bromine. The alkyl radicalR is ether a straight chained alkyl radical having 1 to 8 carbon atomsor a branch chained alkyl radical having 3 to 8 carbon atoms; thealkenyl radical R had 2 to 4 carbon atoms and is especially the allyl ormethallyl radical; and as alkynyl radical, R, has 2 to 5 carbon atoms,and in particular is the propynyl or 1-methyl-2-propynyl radical.

As a cycloalkyl radical, R represents either a monocyclic or apolycyclic radical, e.g. the cyclopropyl, lmethylcyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl radical, orbicyclooctyl, tricyclononyl, tetracyclononyl, octahydromethenopentylanylradicals etc. The alkyl moiety in the alkoxy and alkylthio groupings has1 to 5 carbon atoms in the normal chain or 3 to 5 carbon atoms in thebranched chain. As halogen, R denotes fluorine, chlorine or bromine.

The 2-ureido-benzamides of the Formula I are produced by reacting abenzamide of the Formula II 35, or (b) with the formation components ofa carbamic acid halide of the Formula III, namely phosgene and an amineof the Formula IV,

in an inert solvent or diluent and in the presence of a condensationagent. According to a variation of the process of the invention,2-ureido benzamides of the Formula I, wherein R represents hydrogen, areobtained by reacting a benzamide of the Formula II with an isocyanate ofthe Formula V:

or with a mixture of the isocyanate with a corresponding carbamic acidhalide of the Formula III, optionally in the presence of a condensationagent. In the Formulae II to V, the symbols R to R and n have themeanings given under Formula I.

The reactions are performed in the presence of solvents or diluentswhich are inert to the reactants. Suitable for this purpose arehydrocarbons such as benzene, toluene, xyloys, ether and etherealcompoundssuch as dialkylether, dioxane, tetrahydrofuran,N,N-di-substituted carboxylic acid amides such as dialkyl formamide and'dialkyl acetamide, nitriles such as acetonitrile, chlorinatedhydrocarbons such as chlorobenzene, chloroform and methylene chloride.

The reactions, according to the invention, with a carbamic acid halideare carried out, advantageously, in the presence of a basic condensationagent, e.g. a tertiary amine such as trialkylamine, pyridine orcollidine, or in the presence of an inorganic base, e.g. an alkali metalhydroxide, acetate, hydrogen carbonate, carbonate or of kaolin and 1part of a c'ondensate of naphthaline sulphosphate. phonic ac1d:phendsulphonic acrdzformaldehyde. 3:2:1, Another process for the productlonof the 2-ure1do- WhlCh was diluted q.s. with water (all parts are byweight).

Rye- Mus- Sugar Cucum- Compound Rye grass tard beet bet Cotton VetehMaize 2-(N'-methyl-ureido)-benzamide 0 0 0 v 0 1 1 02-(N,N-dimethyl-ureido)-benzamide 0 1 0 0 0 0' 0 22-(N-ethyl-ureido)-benza.mide 0 0 0 0 0 0 0 2 2-(N-n-propyl-ureido)-bnmmi n 0 0 0 0 0 0 0 3 2-(N'-lsopropyl-ureldo) O 0 0 0 1 2 1 32-(N'-n-butyl-ureldo)Jammm O 0 0 0 0 1 02-(N'-1-methylpropyl-ureido)-benza.mide 0 0 0 0 0 0 0 42-(N-1-methylisopentyureido)-benza.mide 0 0 0 0 0 0. 02-(N-allyl-ureido)- mide 0 0 0 0 0 0 0 42-(N-2-methoxyethylureido)benzamide 3 3 0 0 0 0 0 2-(N-cyelopropylureidob amide 0 0 0 0 0 0 0 0 benzamides of Formula I comprises heating in anaqueous alkaline medium a Z-cyano-phenylurea of Formula VI,

-CEN

R4 (VI) wherein R R R and n have the meanings given under Formula I,with hydrogen peroxide.

The reaction is carried out in a solvent which is miscible with water,such as acetone or dimethylformamide, at a temperature of between 0 and30 C. The pH of the reaction is kept between 8 and 9 by the addition ofa small amount of a base.

The 2-cyano-phenylurea of Formula VI can be obtained by reacting a2-cyano-phenyl-isocyanate of Formula VII (VII) wherein R and n have themeaning given under Formula I, with an amine of Formula IV. The reactiontakes place advantageously in a solvent that is inert to both reactants,such as benzene, toluene, xylene ether.

The new 2-ureido benzamides of the Formula I are crystalline. Theypossess excellent herbicidal properties and can be used in bothpre-emergence and postemergence applications for controlling weeds andwild grasses.

Tests have shown that the new active substances in suitableconcentrations can be used for controlling monocotyl and dicotyl fieldweeds, e.g. the following: species of millet (Panicum sp.), species ofmustard (Sinapis sp.), species of goosefoot (Chenopodiaceaen), alsopanicle grass (Poa annua), foxtail (Alopecurus agrestis), camomile(Matricaria), parsnip (Pastinaca sativa L.) etc., whereby the, usefulplants such as grain, maize, root vegetables, oil plants, vegetables,cotton, sorghum, soya beans and lucerne are not impaired in germinationand in growth.

The herbicidal activity of the compounds of general Formula I isdemonstrated by the following experiment:

A 10% suspension of the active substance was mixed with garden soil sothat a final concentration of 0.5 g. of active substance per liter soilwas attained. The earth was then placed in pots with the following testplants: rye, mustard, rye-grass, sugar-beet, cucumber, cotton, witch andmaize. The pots were then put in a green house and kept at a temperatureof -24 C. and 70% relative humidity in continuous daylight. After 20days the test results were evaluated according to a 10 point scale10=plants unaifected as control 0=plants destroyed 9-1=intermediatestages of damage.

The 10% suspension was prepared from a wettable powder of the followingcomposition: 10 parts of active substance, 0.6 parts of sodiumdibutylnaphthyl sulphonate, 10 parts of sodium aluminium silicate, 78.4points The table shows that these compounds are well suited forcombatting monocotyl and dicotyl weeds in preemergence application.

The 2-ureido benzamides of Formula I, mixed together with the usualadditives, are used as herbicidal agents. Furthermore, the activesubstances can be mixed with fertilizers and applied in this form. Therange of activity of the benzamides of the invention can be widened byapplying them in admixture with other herbicides, e.g.

with triaziues such as halog'endiamino-s-triazines, alkoxy andalkylthiodiamino-s-triazines, diazines, such as uracils, pyridazines,phenols, aliphatic carboxylic acids and halogen carboxylic acids,halogenated benzoic acids and halogenated phenylacetic acids,aryloxyalkane carboxylic acids and aryloxyalkane sulphonic acids,pyridine carboxylic acids, amides, thiamides, hydrazides, esters andnitriles of similar carboxylic acids, carbamic acid esters andthiocarbamic acid esters, quaternary ammonium compounds, ureas,inorganic salts etc., specially with:

2-ch1oro-4,6-bis- (ethylamino) -s-triazine2-chloro-4-ethylamino-6-isopropylamino-s-triazine2-chloro-4,6-bis-(methoxypropylamino)-s-triazine; 2-methoxy-4,6-bis-(isopropylamino -s-triazine2-methylmercapto-4-methoxypropylamino-isopropylamino-s-triazine2-methylmercapto-4,6-bis(isopropylamino)-s-triazine2-methylmercapto-4,6-bis- (ethyl amino -s-triazineZ-methylmercapto-4-ethylamino-6-isopropylamino-striazine2-rnethoxy-4,6-bis-(ethylamino)-s-triazine,2-methoxy-4-ethylamino-6-isopropylamino-s-triazine,2-chloro-4,6-bis(isopropylamino)-s-triazine,5-bromo-3-sec.butyl-6-methyl-uracil,3-cyclohexyl-5,G-trimethylene-uracil, 5-amin0-5-chlorol-phenyl-pyridazone- (6)3,6-dioxo-1,2,3,G-tetrahydropyridazine, Dinitro-sec.butylphenol andsalts thereof, Pentachlorophenol and salts thereof, Trichloroacetic acidand salts thereof, 2,2-dichloropropionic acid and salts thereof,2-chloro-N,N-diallylacetic acid amide,N-(3',4'-dichlorophenyl)-cyclopropane carboxylic acid amide, Maleic acidhydrazide, 2,3,6-trichlorobenzoic acid and salts thereof,2,3,5,6-tetrachlorobenzoic acid and salts thereof,'2-methoxy-3,5,6-trichlorobenzoic acid and salts thereof,2-methoxy-3,6-dichlorobenzoic acid and salts thereof,3-amino-2,5-dichlorobenzoic acid and salts thereof,3-nitro-2,S-dichlorobenzoic acid and salts thereof,2-methyl-3,S-dichlorobenzoic acid and salts thereof,2-methyl-3,S-dichlorobenzoic acid and salts thereof,2,6-dichlorobenzonit1ile, 2,6-dichloro-thiobenzamide,2,3,6-trichlorophenyl acetic acid and salts thereof,2,4-dichlorophenoxyacetic acid and salts thereof,2,4,S-trichlorophenoxyacetic acid and salts and esters thereof, p v(2-methyl-4-chlorophenoxy)-acetic acid and salts and esters thereof, v

2-(2,4',5'-trichlor0phenoxy) -propionic acid and salts and estersthereof, 2-(2',4',5-trichlorophenoxy)-ethyl-2,2-dichloropropionate'4-2',4'-dichlorophenoxy)-butyric acid and salts and esters thereof,4-(2'-methyl-4'-chlorophenoxy)-butyric acid and salts and estersthereof, 2,3,G-trichlorobenzyloxypropanol,4-amino-3,5,6-trichloropicolinic acid, N'-cyclooctyl-N-N-dimethyl urea,S-phenyl- 1,1-dimethyl urea, 3-(4l-chlorophenyl)-1,1-dimethyl urea,3-(3'-trifluoromethylphenyl)-1,l-dimethyl urea,3-(3',4dichlorophenyl)-1,l-dimethyl urea,3-(3',4'-dichlorophenyl)-1-n-butyl-1-methyl ureas,3-(3',4'-dichlorophenyl)-1,1,3-trimethyl urea, 3-3',4'-dichlorophenyl)-1, l-diethyl urea,3-(4'-chlorophenyl)-1-methoxy-1-methyl urea,3-(3,4'-dichlorophenyl)-l-methoxy-1-methyl urea, 3-(4'-bromophenyl)-1-methoxy-lmethyl urea,3-(3,4-dichlorophenyl)-3-methoxy-1,l-dimethyl urea,3-(4'-chlorophenoxy-phenyl)-1,1-dimethyl urea,N,N-di-(n-propyl)-S-ethyl-thiolcarbamic acid ester,-N,N-di-(n-propyl)-S-n-propyl-triolcarbamic acid ester,N-ethyl-N-(n-butyl)-S-n-propyl-thiolcarbamic acid ester,N-phenyl-O-isopropyl-carbamic acid ester,N-(m-chlorophenyl)-O-isopropyl-carbamic acid ester,N-(m-chlorophenyl)-O- (4-chloro-2-butinyl)-carbamic acid ester,N-(3',4'-dichlorophenyl)-O-methyl-carbamic acid ester.

The following examples illustrate the production process for thecompounds of Formula I. Where not otherwise expressly stated, thetemperatures are given in degrees centigrade.

EXAMPLE 1 5.7 g. of methyl isocyanate are added dropwise at roomtemperature, (25) to a solution of 13.6 g. of anthranilic acid amide in100 ml. of acetonitrile. The reaction mixture is then heated, whilestirring, for half an hour at 50. After cooling, the precipitate isfiltered off and recrystallized from methanol. The thus obtained2-(N'methylureido)-benzamide has a melting point of 191 (decomposition).

EXAMPLE 2 'A solution of 27.2 g. of anthranilic acid amide and 30 g. oftriethylamine in 200 ml. of absolute toluene is refluxed to boiling andis themmixed dropwise with 32 g. of dimethylcarbamic acid chloride-Thereaction mixture is then refluxed for a further hour. The precipitateobtained after cooling is filtered off and is slurried in water. Afterrecrystallizing from isopropanol, the obtained 2-(N,N-dimethyl-ureido)-benzamide has a melting point of 185-.-186(decomposition).

EXAMPLE 3 50 ml. of an aqueous hydrogen peroxide solution are addeddropwise during 30 minutes at a temperature of to 20 to a solution of5.1 g. of 2-(N'-methoxy-N'- methyl-ureido)-benzonitrile in 30 ml. ofacetone. By adding 1 ml. of 2 N sodium hydroxide solution the pH of thereaction mixture is kept between 8 and 9. The mixture is stirred for 12hours at room temperature and the precipitate formed is filtered. The 2-(N'-methoxy-N'- methyl-ureido)-benzamide thus obtained melts at 181- 183(decomposition).

.The 2 (N' methoxy-N-methyl-ureido)-benzonitrile used as startingmaterial is obtained as follows:

A solution of 10.5 g. of '2-cyano-phenyl-isocyanate in 60 ml. of benzeneis added at a temperature of 10-15 to another solution of 4.9 g. ofN-methoxy-N-methylamine in 40 ml..of benzene. The solvent is thenremoved under vacuo and the residue is recrystallized from hex- 6 ane.Thus 2-(N'-methoxy-N'-methyl ureido) benzonitrile having an MP. of 71-72is obtained.

In the ways described in the previous examples, the 2-ureido benzamideslisted in the following table are obtained:

Compounds 2-(N-methy1-ureido)-benzamide.

1 Decomp.

The production of herbicidal compositions according to the invention iscarried out in a manner known per se by the intimate mixing and grindingof the active substances of the General Formula I with suitablecarriers, optionally with the addition of dispersion agents or solventswhich are inert to the active substances. The active substances canexist and be used in the following forms:

as solids: dusts, sprinkling agents, granulates, coated granules,impregnated granules and homogeneous granules;

as concentrates of active substances dispersible in water:

wettable powder, pastes, emulsions; A

as liquids: solutions, aerosols.

To produce the solid forms (dusts, sprinkling agents, granulates), theactive substances are mixed with solid carriersSuitable carriers are,e.g. kaolin, talcum, bole, loess, chalk, limestone, ground limestone,ataclay, dolomite, diatomaceous earth, precipitated silicic acid,alkaline earth silicates, sodium and potassium aluminium silicates(feldspar and mica), calcium and magnesium sulphates, magnesium oxide,ground synthetic plastics, fertilizers such as ammonium sulphate,ammonium phosphate, ammonium nitrate, ureas, ground vegetable productssuch as grain flour, bark flour, sawdust, ground nut shells, cellulosepowder, residues of plant extractions, active charcoal, etc. Thesecarriers can be used sepa: rately or they can be mixed with each other.

The grain size of the carriers is, for dusts, advantageously up to ca.0.1 mm., for sprinkling agents it is ca. 0.075 to 0.2 mm. and forgranulates 0.2 mm. upwards.-

The concentrations of active substances in the solid preparations are,as a rule, 0.5 to of the total weight,

To these mixtures can also be added additives which stabilize the activesubstance and/or non-ionic, anionactive and cation-active substances,which, for example, improve the adhesion of the active substances onplants and parts of plants (glues and adhesives) and/or ensure a betterwettability (wetting agents) and also dispersibility (dispersingagents). The following are examples of adhesives: olein-chalk mixtures,cellulose derivatives (methyl cellulose, carboxymethyl cellulose),hydroxyethyl glycol ethers of monoand dialkyl phenols having 5-15ethylene oxide radicals per molecule and 8 to 9 carbon atoms in thealkyl radical, lignin sulphonic acids, their alkali and alkaline earthmetal salts, polyethylene glycol ethers (Carbowaxes), fatty alcoholpolyethylene glycol ethers having 5 to 20 ethylene oxide radicals permolecule and 8 to 18 carbon atoms in the fatty alcohol part,condensation products of ethylene oxide, propylene oxide, polyvinylpyrrolidones, polyvinyl alcohols, condensation products ofurea/formaldehyde as well as Latex products.

Concentrates of active substances which can be dispersed in water(wettable powders), pastes and emulsions concentrates, are agents whichcan be diluted with water to give any desired concentration. Theyconsist of active substances, carriers, optionally additives whichstabilize the active substance, surface agent substances andanti-foaming agents and, optionally, solvents. The concentration ofactive substance in these agents is to 80% of the total weight of thelatter.

The wettable powders and pastes are obtained by mixing and grinding theactive substances with dispersing agents and pulverulent carriers insuitable devices until homogeneity is attained. Suitable carriers are,for example, those previously mentioned for solid preparations. It isadvantageous in some cases to use mixtures of different carriers.Suitable dispersing agents are, e.g. condensation products ofsulphonated naphthalene and sulphonated naphthalene derivatives withformaldehyde, condensation products of naphthalene or of naphthalenesulphonic acids with phenol and formaldehyde, also alkali, ammonium andalkaline earth metal salts of lignin sulphonic acid, also alkylarylsulphonates, alkali and alkaline earth metal salts of dibutylnaphthalene sulphonic acid, fatty alcohol sulphates such as salts ofsulphated fatty alcohol glycol ethers, the sodium salt of oleylethionate, the sodium salt of oleyl methyl tauride, ditertiary acetyleneglycols, dialkyldilauryl ammonium chloride and fatty acid alkali andalkaline earth metal salts.

Examples of anti-foaming agents are: silicones etc. The activesubstances are so mixed, ground, sieved and strained with the abovementioned additives that the solid particle size in wettable powdersdoes not exceed 0.02-0.04 mm. and in the case of pastes 0.003 mm. Toproduce emulsion concentrates and pastes, dispersing agents such asthose stated in the previous sections, organic solvents and water areused. Examples of solvents are: alcohols, benzene, xylenes, toluene,dimethyl sulphoxide and mineral oil fractions boiling between 120 and350 C. The solvents much be practically without smell, not phytotoxic,inert to the active substances and not easily inflammable.

In addition, the agents according to the invention can be used in theform of solutions. For this application, the active substance orsubstances of the General Formula I are dissolved in suitable organicsolvents, mixtures of solvents or in water. Aliphatic and aromatichydrocarbons, chlorinated derivatives thereof, alkyl naphthalenes,mineral oils, on their own or mixed with each other, can be used asorganic solvents. The solvents should contain the active substanceswithin a concentration range of 1 to 20% calculated on the total weightof the resulting solution.

Other biocidal active substances or agents can be mixed with thedescribed compositions according to the invention. Thus in addition tothe stated compounds of the General Formula I and other herbicides, thenew agents can also contain, e.g. insecticides, fungicides,bactericides, fungistatics, bacteriostatics or nematocides in order towiden the range of action. The compositions according to the inventioncan also contain fertilizers, trace elements etc.

Forms of preparation of these active substances are described in thefollowing. Where not otherwise expressly stated, the terms parts andpercentages are given by weight.

Wettable powder 1 The following constituents are used to produce (a) a10% wettable powder, and (b) a 25% wettable powder:

10 parts of 2-(N-methyl-ureido):benzamide 10 parts of lignin sulphonicacid calcium salt 2 parts of adhesive consisting of 50% polyvinyl-pyrerolidone and 50% Champagne chalk 38 parts of kaolin 40 parts ofChampagne chalk 25 parts of 2-(N'-ethyl-ureido)-benzamide v 5 parts ofcondensation products of naphthalene sulphonic acid, phenol sulphonicacids and formaldehyde in the ratio 312:0.5

4 parts of dibutyl naphthyl sulphonate sodium salt 1 part ofmethyl-oleyl-tauride sodium salt 15 parts of silicic acid 25 parts ofneutral sodium aluminum silicate 25 parts of kaolin The stated activesubstances are coated on to the corresponding carriers (kaolin andchalk) and then mixed and ground with the listed additives. A wettablepowder is obtained having excellent wettability and suspensionproperties. Suspensions of any desired active substance concentrationcan be prepared from this wettable powder by diluting with water.

Emulsion concentrate The following constituents are mixed together toproduce a 25 emulsion concentrate:

25 parts of 2-(N'-n-propyl-ureido)-benzamide 35 parts of methyl ethylketone 30 parts of xylol and 10 parts of isooctyl-phenyl polyethyleneglycol This concentrate can be diluted with water to obtain emulsions ofsuitable concentrations. Such emulsions are suitable for controllingweeds in cultivated plantations, for which purpose application ofamounts of about 0.5 to 3 kg. of a compound of Formula I per hectare oftreated soil is recommended.

We claim:

1. A herbicidal composition comprising (1) a herbicidally efiectiveamount of a compound of the formula wherein R represents halogen, alkylor alkoxy of at most 5 carbon atoms; R represents hydrogen or alkyl ofat most 5 carbon atoms; R represents hydrogen, alkyl or alkoxy of atmost 5 carbon atoms; R represents alkyl, alkenyl or alkynyl of at most 8carbon atoms, halogeno alkyl of at most 5 carbon atoms, alkoxyalkyl oralkylmercaptoalkyl having at most 5 carbon atoms, or cycloalkyl havingfrom 3 to 10 carbon atoms; and n represents a whole number of from 0 to3; and (2) an agriculturally 5. A method for controlling undesirableplant growth which comprises applying thereto a herbicidall eifectiveamount of a compound of the formula:

| H R: R6

wherein R represents halogen, alkyl or alkoxy of at most carbon atoms,

R represents hydrogen or lower alkyl,

R represents hydrogen alkyl or alkoxy of at most 5 carbon atoms,

R represents alkyl, alkenyl or alkynyl of at most 8 carbon atoms;halogeno-alkyl of at most 5 carbon atoms; alkoxyalkyl oralkylniercaptoalkyl having at most 5 carbon atoms; or cycloalkyl havingfrom 3 to 10 carbon atoms; and

n represents a whole number from 0 to 3.

6. A method as defined in claim 5 wherein said compound is2-(N'-methoxy-N'-methyl-uredio)-benzamide.

7. A method as defined is claim 5 wherein said compound is2-(N-methyl-ureido)-benzamide.

8. A method according to claim 5 in which, in the compound, n represents0; R represents hydrogen; R represents hydrogen or methyl; and Rrepresents alkyl of at most six carbon atoms, allyl, methoxyethyl orcyclopropyl.

References Cited UNITED STATES PATENTS 3,434,822 3 /1969 Wilson et a171-120 X 3,641,143 2/1972 Richter at al 71 3,642,891 2/1972 Teoch 71-1203,658,892 4/1972 Martin et a1. 71-415 JAMES 0. THOMAS, JR., PrimaryExaminer us. 01. X.R.

Patent No. 3,806,334

r STATES PATENT (SFFICE CERTIFICATE OF CORRECTION K Dated April 23, I974e Karl Hoegerle, Jean-Claude Muller, Christian V oge1 & I R p i It iscertified that; error appears in the aboireidentified patent and thatsaid Letters Patent are hereby corrected as' shown below;

In the heading, insert:

Claims priority, application Switzerland, March 29, 1968,

Signed and sealed this 10th day of Septemberl97h.

(SEAL) Attest: a

MCCOY M. GIBSON, JR. c. MARSHALL DANN Attesting Officer CommissionerofPatents ORM o-mso (10-69)

